Bought a 97 F-150 a couple of months ago. Had check engine light, but guy we bought it from swore it was because it had a missing gas cap. Replaced gas cap. Still had a check engine light.
Took it to Autozone last night. They said it is throwing the following:

O2 Sensor Bank 2 Sensor 1
Fuel/Air Metering

Autozone said that the O2 sensor was easy to replace, but that the Fuel/Air Metering was something that only the dealership could fix.

Truck gets decent mileage, does run a little rough at an idle, but otherwise is fine- any ideas? I don't want to take it to the dealership if I can avoid it. Always want way to much $$$. Don't want to replace O2 Sensors if I don't need to either. FYI-Truck does have 100K on it, and I'm not sure if any sensor has ever been replaced.

Any advice?

 

I had the same code result, and got a new O2 sensor for the passenger side before cat converter O2 sensor. However, under the vehicle I found it really tough to work with.

What is the best way to get to the O2 sensor? I thought maybe to drop exhaust pipe before the cat converter to get to the sensor, but the bolts are on tight, maybe rusted on so I need a longer wrench handle.

Any toughts?

Just got my 99 Expedition and I am unfamiliar with Fords.

Thanks,
Matt

 

Autozone just told me my 1998 F150 4x4 5.4L oxygen sensor (bank 2 sensor 1) was also bad. Did replacing yours help? My check engine light is still on too. Where was yours located? I can't seem to find mine and haven't decided if I should replace it.

 

O2 sensors on a 5.4L arent all that bad. The two down stream ones are a breeze. The upper driver side one isnt all that bad, but the upper passenger side is the WORST EVER. You can't use the special O2 sockets simply because it wont fit (on my 98 F150 4x4). What I had to do is use an open end wrench. I believe its a 7/8???? Can't recall the exact size but if you loosen the exhaust manifold, pull it down as far as possible and use an open end wrench, it'll loosen. The next pain is disconnecting the wiring harness. That's the only hard part to it. I replaced mine after Autozone said I had bad O2 sensors. My problem ended up being a vacuum leak on the back of the intake. If you're having bad idiling problems, get a can of starting fluid and spray around the intake seals, any vacuum lines, and areas where extra air my be coming in. If you do this while the engine is idiling, and you hear the engine rev up slightly, then you have some sort of intake leak or vacuum leak. This initial check will save you time and money.

 

Prior to swapping out the HO2S, get the actual number for the DTC. AutoZone has a way of making the wrong guess at what is wrong. The HO2S is the reporting device, but what is it reporting ( that is what the code number is ). This could be something like a P017x number for the DTC, which can be a number of things aside from a faulty HO2S, but it [i/]might[/i] be the HO2S. Un-mettered air getting into the system can cause an error to be reported by the HO2S, but the actual problem is something like a cracked VAC line, or after a air filter change, one of the hoses on the intake tobe to the T/B is loose ( after the MAFS ).
These are just examples of what others have seen, without the actual number, I'd rather not send you on a wild goose chase.

Let us know.

 

i have a 98 f-150 with dtc codes p1151 and p0171 and p0174.. 5.4 v8... can someone tell me where is bank 2 sensor 1?

 

I have a 98 expedition 4.6. Started running ROUGH! took it to Autozone and the computer said that 2 of my oxygen sensors were bad, replaced them, helped for a few weeks, then started it again, Took it back and computer said it was a different oxygen sensor. Had that one replaced also. Still runs terribly. Took it back and now they say "the oxygen sensors are reading too lean". Anyone know what this means and what I have to do to fix it? HELP PLEASE!

 

Look for a vacuum leak...
Also....
Change the fuel filter, clean the throttle body and IAC.....

 

Cut of the wires near the top of the bad O2 sensor, break off the ceramic portion like you could a spark plug so you can get on the thing to loosen it.

 

listen to your engine running with the hood up, then push, pull and squish any vacuum lines you can grab up by the intake, starting at pcv valve. Mine was cracked under a clamp, found it just by listening. $7 dollar vacuum line and fixed. Good luck.

 

I know lol. Have a look at your warm idle rpms in park and report back. Easy to pinpoint the problem that way for the 97-03's.. But! I need to know EXACT warm idle rpms or you'll have to run thru a procedure. More work, more time.

 

Since I have been on here we have changed all o2 sensors and had it put on computer. It still read lean and also said something about the EGR sensor. Replaced EGR valve and sensor and still runs terrible. Warm RPM's are between 700 and 800. It shakes and chokes. Running terrible. Please help.

 

I posted on here but did not inclide your quote. Just learning how to work this site. Anyway if you could check my previous post the info is in it. Thank you.

 

Yea, you have to post the DTC's or it's impossible to help. That's what the DTC's do, -point you or someone who knows in the correct direction. There's a lot more than one for each area you've mentioned. So write them down so we can help.
Just so you know, -a simple DTC scanner is a lot cheaper than the parts you've thrown at it so far. They're like 30 bucks, -even cheaper @ Harbor Freight or on eBay. Just sayin, -there's ways to go about this much cheaper.
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So warm idle rpms jump from 700-800 and do not settle ? Constant needle movement ? That's a first, - something is very screwed up lol. Sounds like a PCM problem (the computer). Like I said that's a first, when this sort of thing happens it ends up being programming.

See yuh in another 2 months.. Maybe...

 

Probably intake manifold problem, pull it and replace the gaskets, also check for clogged passageways up by the throttle body. Try carb cleaner spray, it is a little safer than spray starter fluid. Won't blow your eyebrows off quite so readily. look closely for vacuum leaks, cracked vacuum hoses, PCV and its hose, is the 4x4 acting up?, those sort of thing.